Meyer Sound 750-LFC Operating Instructions Manual

OPERATING INSTRUCTIONS

750-LFC Compact Low-Frequency Control Element

LF

Keep these important operating instructions. Check www.meyersound.com for updates.

©2018
Meyer Sound. All rights reserved.
750-LFC Operating Instructions, PN 05.271.005.01 B

The contents of this manual are furnished for informational purposes only, are subject to change without notice, and should not be con­strued as a commitment by Meyer Sound Laboratories Inc. Meyer Sound assumes no responsibility or liability for any errors or inaccura­cies that may appear in this manual. Except as permitted by applicable copyright law, no part of this publication may be reproduced,
stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, recording or otherwise, without prior writ­ten permission from Meyer Sound.

Compass RMS, GuideALink, Intelligent AC, LEO-M, LYON, LINA, MAPP, QuietCool, RMS, RMServer, and all alpha-numeric designations
for Meyer Sound products and accessories are trademarks of Meyer Sound. Callisto, Galileo, LEO, Meyer Sound, the Meyer Sound wave
logo, MICA, QuickFly, REM, SIM, and TruPower are registered trademarks of Meyer Sound Laboratories Inc. (Reg. U.S. Pat. & Tm. Off.). All
third-party trademarks mentioned herein are the property of their respective trademark holders.

ii

CONTENTS

Chapter 1: Introduction 5

How to Use This Manual 5
750-LFC Compact Low-Frequency Control Element 5
Native Mode 6
Optimal Mid-High Loudspeaker to Subwoofer Ratio 8

Chapter 2: Power Requirements 9

AC Power Distribution 9
AC Connectors 10
Wiring AC Power Cables 11
750-LFC Voltage Requirements 11
750-LFC Current Requirements 11
Intelligent AC Power Supply 12
Electrical Safety Guidelines 13
MDM-832 Distribution Module 13

Chapter 3: Amplification and Audio 15

Audio Connectors 15
Cable Rings 16
TruPower Limiting 16
Amplifier Cooling System 17
On/Status LED 17

Chapter 4: QuickFly Rigging 19

Important Safety Considerations! 19
750-LFC Rigging Options 19
Groundstacking 750-LFC Loudspeakers 21
750-LFC Cardioid Arrays 21
MRK-750 Rigging Kit 21
750-LFC GuideALinks 22
Pole-Mount Receptacle 24
MCF 750 Caster Frame 25

Chapter 5: Remote Monitoring System (RMS) Option 27

Compass RMS Software 27
RMS Module 27
Neuron ID for RMS Module 28
Resetting the RMS Module 28

Chapter 6: System Design and Integration Tools 29

MAPP System Design Tool 29
SIM 3 Measurement System 30

Appendix A: Rain Hoods 31

750-LFC Rigid Rain Hood 31
750-LFC Foldable Rain Hood 31

Appendix B: 750-LFC Dimensions 33

Appendix C: 750-LFC Specifications 35

iii

CONTENTS

iv

CHAPTER 1: INTRODUCTION

!

HOW TO USE THIS MANUAL

Make sure to read these instructions in their entirety before
configuring a Meyer Sound loudspeaker system. In particu­lar, pay close attention to material related to safety issues.

As you read these instructions, you will encounter the fol­lowing icons for notes, tips, and cautions:

NOTE: A note identifies an important or useful

piece of information relating to the topic under

discussion.

TIP: A tip offers a helpful tip relevant to the topic

at hand.

CAUTION: A caution gives notice that an

action may have serious consequences and
could cause harm to equipment or personnel, or
could cause delays or other problems.

Information and specifications are subject to change.
Updates and supplementary information are available at

www.meyersound.com

Meyer Sound Technical Support is available at:

.

750-LFC COMPACT LOW-FREQUENCY
CONTROL ELEMENT

Meyer Sound’s 750-LFC compact low-frequency control
element reproduces low frequencies at high, continuous
output levels with extremely low distortion. The 750-LFC
offers the same sonic linearity as Meyer Sound’s 900 LFC
low-frequency control element in a smaller, lighter cabinet,
making it ideal for building scalable systems to suit portable
applications or fixed installations of any size.

■ Tel: [phone]

■ Tel: [phone] (after hours support)

■ Web: www.meyersound.com/support

■ Email: [e-mail]

Figure 1: 750-LFC Compact Low-Frequency Control Element

A newly-designed class D amplifier affords unprecedented
efficiency to the 750-LFC, significantly lowering distortion
while reducing power consumption and operating tempera­ture. The onboard amplifier and control circuitry are con­tained in a single, field-replaceable module.

In addition to pairing with LINA

™

systems, the 750-LFC inte­grates easily with other Meyer Sound loudspeaker systems,
including LEOPARD

™

and ULTRA Series loudspeakers.

LINA and 750-LFC can be driven by Meyer Sound’s Galileo
GALAXY

™

array processors, which provides matrix routing,
alignment, and processing for array components. To guaran­tee optimum performance, systems with the 750-LFC
should be designed with Meyer Sound’s MAPP

™

software.

LINA and 750-LFC loudspeakers work with Meyer Sound’s

™

RMS

remote monitoring system, which provides compre­hensive monitoring of system parameters from a Mac
Windows

®

-based computer.

®

or

5

CHAPTER 1: INTRODUCTION

Figure 2: 750-LFC and LINA array

The 750-LFC is available with or without Meyer Sound’s
QuickFly
MRK-750 rigging kit, the 750-LFC’s captive GuideALinks

®

rigging. When equipped with the optional

™

allow it to be flown from the MG-MINA/LINA/750 LFC multi­purpose grid in LINA arrays without any transition frame
between the 750-LFC and LINA. 750-LFCs can also be
flown separately as a subwoofer array with variable splay
angles from 0 to 5 degrees. The 750-LFC can be configured
in cardioid arrays to reduce output behind the loudspeakers.

In addition, when equipped with the optional MRK-750 rig­ging kit, the 750-LFC can be used to create groundstacked
arrays without a transition frame between the 750-LFC and
LINA. The MG-MINA/LINA/750-LFC grid can also be used for
to create a wider base for groundstacks.

Both versions of the 750-LFC can be transported in stacks
with the optional MCF-750 caster frame. Please specify the
caster frame for the version when placing the order.

Figure 3: 750-LFC and LINA groundstack (left) and pole-mount (right)

NATIVE MODE

LINA and 750-LFC loudspeakers are optimized for use in cer­tain flown and groundstacked configurations without any
array compensation or other signal processing. This capabil­ity, called Native mode, allows LINA/750-LFC systems to be
deployed quickly with excellent results, without equalization,
tuning, or use of presets.

To use LINA and 750-LFC loudspeakers in Native mode,
send an identical, unmodified signal to each element in the
array. The simplest way to accomplish this is by looping the
same, unprocessed source signal through all array elements.

The following coplanar configurations can be used in Native
mode (without any signal processing):

■ Flown mixed arrays of LINAs and 750-LFCs (Figure 4)

■ Flown separate arrays of LINAs and 750-LFCs (Figure 5)

■ Mixed groundstacks of LINAs and 750-LFCs (Figure 6)

■ LINAs pole-mounted on top of 750-LFC (Figure 3 right)

The 750-LFC Integral pole-mount allows to easily place one
or two LINAs on top using the MUB-LINA or MYA-LINA
yoke. In addition the pole mount can be use to pair the
750-LFC with UltraSeries loudspeakers.

6

750-LFC OPERATING INSTRUCTIONS

Source Audio

Source Audio

Source Audio

!

Figure 6: Mixed Groundstack (ratio 2:2)

Figure 4: Flown Mixed Array (ratio 3:1)

Figure 5: Flown Separate Arrays (ratio 8:3)

NOTE: Native mode should not be used with

more advanced configurations, such as those
where 750-LFCs and LINAs are not coplanar, or those
requiring delay offsets to align subsystems or to cre­ate directional low-frequency control. These systems
require additional processing.

NOTE: For Native mode to work properly, the

source signal must be correctly configured
with the appropriate gain structure.

CAUTION: Make sure that all cabling for

looped loudspeakers is wired correctly (Pin 1
to Pin 1, Pin 2 to Pin 2, etc.) to prevent the polarity
from being reversed. If one or more loudspeakers in a
system have reversed polarity, frequency response
and coverage will be significantly degraded.

7

CHAPTER 1: INTRODUCTION

OPTIMAL MID-HIGH LOUDSPEAKER TO SUB­WOOFER RATIO

The ideal ratio of mid-high loudspeakers to 750-LFC sub­woofers depends on the following:

■ Loudspeaker model

■ System configuration

■ Frequency content of source material

■ Headroom required for low frequencies

For LINA applications, the ratios shown in the figures above
yield good results.

8

CHAPTER 2: POWER REQUIREMENTS

!

!

Neutral

Earth/Ground

Line 1 (120 V AC)

Line 3 (120 V AC)

Line 2 (120 V AC)

Loudspeaker

(120 V AC)

Loudspeaker

(120 V AC)

Loudspeaker

(120 V AC)

Neutral

Earth/Ground

Loudspeaker

(208 V AC)

Loudspeaker

(208 V AC)

Loudspeaker

(208 V AC)

Line 1 (120 V AC)

Line 3 (120 V AC)

Line 2 (120 V AC)

The 750-LFC combines advanced loudspeaker technology
with equally advanced power capabilities. Understanding
power distribution, voltage and current requirements, and
electrical safety guidelines is critical to the safe operation of
the 750-LFC.

AC POWER DISTRIBUTION

All components in an audio system (self-powered loud­speakers, mixing consoles, and processors) must be prop­erly connected to an AC power distribution system, ensuring
that AC line polarity is preserved and that all grounding
points are connected to a single node or common point
using the same cable gauge (or larger) as the neutral and
line cables.

CAUTION: Make sure the voltage received by

the 750-LFC remains within its 90–264 V
AC operating range. In addition, the ground line must
always be used for safety reasons and the line-to­ground voltage should never exceed 250 V AC (typi­cally 120 V AC from line to ground).

CAUTION: Before applying AC power to any

Meyer Sound self-powered loudspeaker, make
sure that the voltage potential difference between the
neutral and earth-ground lines is less than 5 V AC
when using single-phase AC wiring.

120 V AC, 3-Phase Wye System (Single Line)

Line-Neutral-Earth/Ground

Figure 7 illustrates a basic 120 V AC, 3-phase Wye distribu­tion system with the loudspeaker load distributed across all
three phases, with each loudspeaker connected to a single
line and common neutral and earth/ground lines. This sys­tem delivers 120 V AC to each loudspeaker.

Figure 7: 120 V AC, 3-Phase Wye System (Single Line to Loudspeakers)

120 V AC, 3-Phase Delta System (Two Lines)

Line-Line-Earth/Ground

Figure 8 illustrates a 120 V AC, 3-phase Delta distribution
system with each loudspeaker connected to two lines and a
common earth/ground line. This configuration is possible
because the 750-LFC tolerates elevated voltages from the
ground line and does not require a neutral line. This system
delivers 208 V AC to each loudspeaker.

NOTE: Improper grounding of connections

between loudspeakers and the rest of the
audio system may produce noise or hum, or cause
serious damage to the input and output stages of the
system’s electronic components.

Figure 8: 120 V AC, 3-Phase Delta System (Two Lines to Loudspeakers)

TIP: The 120 V AC, 3-phase Delta system with

two lines is recommended because it allows
loudspeakers to draw less current than with single­line systems, thereby reducing voltage drop due to
cable resistance.

9

CHAPTER 2: POWER REQUIREMENTS

Neutral

Earth/Ground

Line 1 (230 V AC)

Line 3 (230 V AC)

Line 2 (230 V AC)

Loudspeaker

(230 V AC)

Loudspeaker

(230 V AC)

Loudspeaker

(230 V AC)

!

!

230 V AC, 3-Phase Wye System (Single Line)

Line-Neutral-Earth/Ground

Figure 9 illustrates a basic 230 V AC, 3-phase Wye distribu­tion system with the loudspeaker load distributed across all
three phases, with each loudspeaker connected to a single
line and common neutral and earth/ground lines. This sys­tem delivers 230 V AC to each loudspeaker.

Figure 9: 230 V AC, 3-Phase Wye System (Single Line to Loudspeakers)

CAUTION: For 230 V AC 3-phase systems,

never use a Delta connection. Connecting two
lines to the AC input of the 750-LFC exceeds the
allowable upper voltage range (275 V AC) and will
damage the loudspeaker.

AC CONNECTORS

The 750-LFC user panel includes two powerCON 20 con­nectors, one for AC Input (blue) and one for AC Loop Output
(gray).

The AC Input connector also supplies power to any addi­tional loudspeakers connected to the loudspeaker’s gray
Loop Output connector.

CAUTION: When looping AC power for loud-

speakers, do not exceed the current capability
of the AC Input connector (20 A) or the included AC
power cable (15 A). Consider the total current draw for
all loudspeakers on the circuit, including the first loud­speaker (see Table 1 on page 10).

AC Loop Output (Gray)

The gray AC Loop Output connector allows multiple
750-LFCs to be looped and powered from a single power
source. The 3-conductor powerCON 20 is rated at 20 A and
uses a locking connector that prevents accidental discon­nections. For applications that require multiple 750-LFCs,
connect the AC Loop Output of the first loudspeaker to the
AC Input of the second loudspeaker, and so forth.

The maximum number of loudspeakers that can be looped
from the AC Loop Output connector is determined by the
voltage of the power source, the current draw of the looped
loudspeakers, the circuit breaker rating, and the rating of the
AC power cable connected to the first 750-LFC loud­speaker.

Table 1: Maximum 750-LFCs that Can Be Looped with AC Power

Circuit Breaker/
Connector Rating

15 A

20 A

115 V AC 230 V AC 100 V AC

1 looped

(2 total)

2 looped

(3 total)

4 looped

(5 total)

6 looped

(7 total)

1 looped

(2 total)

2 looped

(3 total)

AC Input (Left) and AC Loop Output (Right) Connectors

AC Input (Blue)

The blue AC Input connector supplies power to the
750-LFC. The 3-conductor powerCON 20 is rated at 20 A
and uses a locking connector that prevents accidental dis­connections. A 10-foot AC power cable, rated at 15 A, is
included with each loudspeaker. If you replace the included
AC power cable, make sure to use a cable with the appropri­ate power plug (on the other end) for the area in which you
will operate the unit. The 750-LFC requires a grounded out­let. To operate safely and effectively, it is extremely import­ant that the entire system be properly grounded.

10

NOTE: Current draw for the 750-LFC is

dynamic and fluctuates as operating levels
change. The indicated number of loudspeakers that
can be looped assumes that operating levels are nor­mal and not such that loudspeakers are constantly
limiting.

The 750-LFC ships with a gray powerCON 20 cable mount
connector, rated at 20 A, for assembling AC looping cables.
Assembled AC looping cables are also available from Meyer
Sound (P.N. 28.115.032.03): 3.2 ft (1 m), 13 AWG (2.5 mm

2

).

750-LFC OPERATING INSTRUCTIONS

L

N

PE

SIDE FRONT REAR

U.S./Canada, 60 Hz

Black (L)

Europe, 50 Hz

Green (E)

White (N)

Brown (L)

Blue (N)

Green/
yellow (E)

!

!

WIRING AC POWER CABLES

The pins on the gray powerCON 20 cable mount connector
are labeled as follows:

■ L (Line)

■ N (Neutral)

■ PE (Protective Earth or Ground)

Gray powerCON 20 Cable Mount Connector

How AC power cables are wired is determined by the type of
AC power distribution system used (see “AC Power Distri­bution” on page 9). When wiring AC power cables for single­line systems, use one of the following wiring schemes:

750-LFC VOLTAGE REQUIREMENTS

The 750-LFC operates as intended when receiving AC volt­age within the following range:

■ 90–264 V AC, 50–60 Hz

If the voltage drops below 90 V, the loudspeaker uses stored
power to continue operating temporarily; the loudspeaker
powers off if the voltage does not return to its operating
range.

If the voltage rises above 275 V, the power supply could
become damaged.

CAUTION: The power source for the 750-LFC

should always operate within the required oper­ating range, at least a few volts from the upper and
lower ranges. This ensures that AC voltage variations
from the service entry — or peak voltage drops due to
cable runs — will not cause the loudspeaker’s ampli­fier to cycle on and off or cause damage to the power
supply.

750-LFC CURRENT REQUIREMENTS

Current draw for loudspeakers is dynamic and fluctuates as
operating levels change. Since different cables and circuit
breakers heat up at varying rates, it is important to under­stand the following types of current ratings and how they
affect circuit breaker and cable specifications.

AC Wiring Scheme

Wire Color

U.S. / Canada

60 Hz

Black Brown Hot or live (L)

White Blue Neutral (N)

Green Green and Yellow

European

50 Hz

CAUTION: When wiring AC power cables and

distribution systems, it is important to preserve
AC line polarity and connect the earth ground on both
ends of the cable. The 750-LFC requires a grounded
connection. Always use a grounded outlet and plug.
It is extremely important that the system be properly
grounded to operate safely and properly. Do not
ground-lift the AC cable.

Attach to

Terminal

Protective earth /

ground (E or PE)

■ Idle Current — The maximum rms current during idle

periods.

■ Maximum Long-Term Continuous Current — The

maximum rms current during a period of at least
10 seconds. The maximum long-term continuous current
is used to calculate temperature increases for cables, to
ensure that cable sizes and gauges conform to electrical
code standards. The current rating is also used as a rat­ing for slow-reacting thermal breakers, which are recom­mended for loudspeaker power distribution. In addition,
the maximum long-term continuous current can be used
to calculate the AC looping capability for 750-LFC loud­speakers.

■ Burst Current — The maximum rms current during a

period of around 1 second. The burst current is used as
a rating for magnetic breakers. It is also used for calcu­lating the peak voltage drop in long AC cable runs
according to the following formula:

V pk (drop) = I pk x R (cable total)

■ Maximum Instantaneous Peak Current — A rating for

fast-reacting magnetic breakers.

11

CHAPTER 2: POWER REQUIREMENTS

!

You can use the following table as a guide to select cable
gauges and circuit breaker ratings for the system’s operat­ing voltage.

750-LFC Current Draw

Current Draw 115 V AC 230 V AC 100 V AC

Idle 0.39 A rms 0.38 A rms 0.42 A rms

Maximum Long-Term
Continuous

Burst 9.2 A rms 4.4 A rms 10.7 A rms

Maximum Instantaneous
Peak

5.3 A rms 2.7 A rms 6.2 A rms

15.3 A peak 7.8 A peak 18.0 A peak

The minimum electrical service amperage required by a
loudspeaker system is the sum of the maximum long-term
continuous current for all loudspeakers. An additional
30 percent above the minimum amperage is recommended
to prevent peak voltage drops at the service entry.

NOTE: For best performance, the AC cable volt-

age drop should not exceed 10 V (10 percent at
115 V and 5 percent at 230 V). Make sure that even
with AC voltage drops that the voltage always remains
within the loudspeaker’s operating range.

4. On the user panel, the On/Status LED flashes multiple
colors successively.

5. The On/Status LED turns solid green, indicating the
loudspeaker is ready to output audio.

CAUTION: If the On/Status LED does not turn

solid green, or the 750-LFC does not output
audio after 10 seconds, remove AC power immedi­ately and verify that the voltage is within the required
range. If the problem persists, contact Meyer Sound
Technical Support.

INTELLIGENT AC POWER SUPPLY

The 750-LFC’s Intelligent AC™ power supply automatically:

■ Selects the correct operating voltage, allowing interna-

tional use without manually setting voltage switches;

■ Eliminates high inrush currents with soft-start power up;

■ Suppresses high-voltage transients up to several kilovolts;

■ Filters common mode and differential mode radio fre-

quencies (EMI);

■ Sustains operation temporarily during low-voltage periods.

Powering on the 750-LFC

When powering on the 750-LFC, the following startup
events take place over several seconds.

1. Audio output is muted.

2. Voltage is detected and the power supply mode is auto­matically adjusted as necessary.

3. The power supply ramps up.

12

750-LFC OPERATING INSTRUCTIONS

Earth ground

Chassis ground

132132132132132132132132

21

3213213213213213213213

ELECTRICAL SAFETY GUIDELINES

Make sure to observe the following important electrical and
safety guidelines.

■ The powerCON 20 connector should not be engaged or

disengaged when under load or live.

■ The 750-LFC requires a grounded outlet. Always use a

grounded outlet and plug.

■ Do not use a ground-lifting adapter or cut the AC cable

ground pin.

MDM-832 DISTRIBUTION MODULE

The optional MDM-832 Distribution Module simplifies instal­lation by using regular or composite cables to route AC
power, balanced audio, and RMS to multiple LINA and 750­LFC units. This reduces setup and tear-down time for porta­ble systems, and cable clutter for fixed installations.

Meyer Sound offers the MDM Load Calculator program,
which estimates AC power and AC load. This helps design
the AC distribution system using the MDM-832 (or the larger
MDM-5000) distribution modules.

The MDM Load Calculator program and the MDM-832
Operating Instructions (which includes information for the
MDM-832 and MDM-5000) are available for download on
the Meyer Sound website: http://www.meyersound.com

■ Do not exceed the current capability of the 20 A AC Input

connector for the loudspeaker. When looping loudspeak­ers, consider the total current draw for all loudspeakers
on the circuit, including the first loudspeaker.

■ Make sure the AC power cable for the loudspeaker has the

appropriate power plug (on the other end) for the area in
which you will operate the loudspeaker. In addition, the AC
power cable must be rated for the total current draw of all
loudspeakers looped from the power source.

■ Do not operate the unit if the power cable is frayed or

broken.

■ Keep all liquids away from 750-LFC loudspeakers to

avoid hazards from electrical shock.

■ Use the cable rings (see “Cable Rings” on page 16) on

the rear of the 750-LFC cabinet to reduce strain on the
AC power cable (and audio cables). Do not use the cable
rings for any other purpose.

13

CHAPTER 2: POWER REQUIREMENTS

14

CHAPTER 3: AMPLIFICATION AND AUDIO

The 750-LFC’s driver is powered by a proprietary 2-channel,
open-loop, class D amplifier. The audio signal is processed
with correction filters for flat phase and frequency responses
and driver protection circuitry. Each channel has peak and
rms limiters that prevent driver over-excursion and regulate
voice coil temperatures.

Figure 10: 750-LFC User Panel (XLR 5-pin version)

The 750-LFC user panel includes Input and Loop output con­nectors for audio, Limit and On/Status LEDs, and RMS con­nectors and controls (see Chapter 5, “Remote Monitoring
System (RMS) Option”).

NOTE: RMS is optional, so please specify this

feature when placing your order.

AUDIO CONNECTORS

The 750-LFC is available with XLR 3-pin or 5-pin connectors
for audio Input and audio Loop output. XLR 5-pin connec­tors accommodate both balanced audio and RMS signals.

Figure 11: XLR 5-Pin Audio Connectors, Input and Loop Output

Audio Input (XLR 3-Pin or 5-Pin Female)

The XLR 3-pin or 5-pin female Input connector accepts bal­anced audio signals with an input impedance of 10 kOhm.
The connector uses the following wiring scheme:

■ Pin 1 — 1 kOhm to chassis and earth ground (ESD

clamped)

■ Pin 2 — Signal (+)

■ Pin 3 — Signal (–)

■ Pin 4 — RMS (polarity insensitive)

■ Pin 5 — RMS (polarity insensitive)

■ Case — Earth (AC) ground and chassis

NOTE: Pins 4 and 5 (RMS) are included only

with XLR 5-pin connectors.

Pins 2 and 3 carry the input as a differential signal. Pin 1 is
connected to earth through a 1 kOhm, 1000 pF, 15 V
clamped network. This circuitry provides virtual ground lift
for audio frequencies while allowing unwanted signals to
bleed to ground. Make sure to use balanced XLR audio
cables with pins 1–3 connected on both ends. Telescopic
grounding is not recommended and shorting an input con­nector pin to the case may cause a ground loop, resulting in
hum.

TIP: If unwanted noise or hiss is produced by the

loudspeaker, disconnect its input cable. If the
noise stops, there is most likely nothing wrong with the
loudspeaker. To locate the source of the noise, check
the audio cable, source audio, and AC power.

Audio Loop Output (XLR 3-Pin or 5-Pin Male)

The XLR 3-pin or 5-pin male Loop output connector allows
multiple loudspeakers to be looped from a single audio
source. The Loop output connector uses the same wiring
scheme as the Input connector (see “Audio Input (XLR 3-Pin
or 5-Pin Female)” on page 15). For applications that require
multiple 750-LFCs, connect the Loop output of the first
loudspeaker to the Input of the second loudspeaker, and so
forth.

Figure 12: XLR 3-Pin Audio Connectors, Input and Loop Output

NOTE: The Loop output connector is wired in

parallel to the Input connector and transmits
the unbuffered source signal even when the loud­speaker is powered off.

15

CHAPTER 3: AMPLIFICATION AND AUDIO

!

!

Calculating Load Impedance for Looped Audio
Signals

To avoid distortion when looping multiple loudspeakers,
make sure the source device can drive the total load imped­ance of the looped loudspeakers. In addition, the source
device must be capable of delivering approximately 20 dBV
(10 V rms into 600 ohms) to yield the maximum SPL over the
operating bandwidth of the loudspeakers.

To calculate the load impedance for the looped loudspeak­ers, divide 10 kOhms (the input impedance for a single loud­speaker) by the number of looped loudspeakers. For
example, the load impedance for 10 750-LFCs is 1000 ohms
(10 kOhms / 10). To drive this number of looped loudspeak­ers, the source device should have an output impedance of
100 ohms or less. This same rule applies when looping
750-LFCs with other Meyer Sound self-powered loudspeak­ers.

NOTE: Most source devices are capable of

driving loads no smaller than 10 times their

output impedance.

TIP: Audio outputs from Meyer Sound’s GALAXY,

Galileo, and Callisto loudspeaker processors are
rated at 50 ohms. This allows each output to drive up
to 20 Meyer Sound (10 kohm) loudspeakers without
distortion.

CAUTION: Make sure that all cabling for

looped loudspeakers is wired correctly (Pin 1
to Pin 1, Pin 2 to Pin 2, and so forth) to prevent the
polarity from being reversed. If one or more loud­speakers in a system have reversed polarity, fre­quency response and coverage will be significantly
degraded.

CABLE RINGS

Two cable rings are provided on the rear of the 750-LFC
cabinet. Power and audio cables should be tied off to the
rings to reduce strain on the cables and prevent damage to
them during installation.

Figure 13: Cables Tied Off to Cable Ring

CAUTION: 750-LFC cable rings should only be

used to reduce strain on cables. The cable

rings should not be used for any other purpose.

TRUPOWER LIMITING

The 750-LFC employs Meyer Sound’s advanced TruPower®
limiting. Conventional limiters assume a constant loud­speaker impedance and set the limiting threshold by mea­suring voltage alone. This method is inaccurate because
loudspeaker impedances change as frequency content in
the source material changes, and as thermal values for the
loudspeaker’s voice coil and magnet vary. Consequently,
conventional limiters often begin limiting prematurely, which
reduces system headroom and dynamic range.

In contrast, TruPower limiting calculates varying loud­speaker impedances by measuring both current and voltage
to compute the actual power dissipation in the voice coil.
This improves performance, both before and during limiting,
by allowing the driver to produce the maximum SPL across
its entire frequency range, while also retaining signal peaks.
TruPower limiting also eliminates power compression at high
levels over lengthy periods, which helps regulate voice coil
temperatures, thereby extending the life of the driver.

16

750-LFC OPERATING INSTRUCTIONS

!

!

!

LF Limit LED

The 750-LFC is low-frequency driver is powered by two
amplifier channels, one for each voice coil, that are routed to
a single limiter. When a safe power level is exceeded in
either channel, limiting is engaged for both channels and the
LF Limit LED lights on the user panel (the HF Limit LED is
disabled for the 750-LFC).

Figure 14: 750-LFC Limit LEDs (HF LED Disabled)

When engaged, the limiter not only protects the drivers but
also prevents signal peaks from causing excessive distor­tion in the amplifier channels, thereby preserving headroom
and maintaining smooth frequency response at high levels.
When levels return to normal, below the limiter threshold,
limiting ceases.

The 750-LFC performs within its acoustical specifications at
normal temperatures when the LF Limit LED is unlit, or
when the LED is lit for 2 seconds or less and then turns off
for at least 1 second. If the LED remains lit for longer than
3 seconds, the loudspeaker enters hard limiting where:

■ Increases to the input level have no effect

■ Distortion increases due to clipping

■ Drivers are subjected to excessive heat and excursion,

thereby compromising their lifespan

CAUTION: The Limit LEDs indicate when a

safe, optimum level is exceeded. If a 750-LFC
loudspeaker system begins to limit before reaching
the desired SPL, consider adding more units to the
system.

AMPLIFIER COOLING SYSTEM

The 750-LFC employs natural convection in its cooling sys­tem. The amplifier’s heat sink provides natural convection
cooling from the air flowing near its fins. When exposed to
high ambient temperatures or when driven continuously at
high output levels, an ultra low-noise, variable-speed fan cir­culates air internally to keep the 750-LFC at a safe operating
temperature.

CAUTION: To prevent the 750-LFC from over-

heating, allow at least 6 in behind the loud­speaker for proper ventilation. During extreme
operation the 750-LFC’s heat sink can reach tem­peratures up to 80° C (176° F). Wait 15 minutes for
the unit to cool before touching.

ON/STATUS LED

During normal operation, when the 750-LFC is powered on,
the On/Status LED is solid green. If the loudspeaker
encounters a hardware fault, or the unit begins to overheat,
the LED flashes red. In some instances, the loudspeaker will
continue to output audio while the LED flashes red, though
with a reduction in the limiter thresholds (and gain) to protect
the loudspeaker.

If a loudspeaker is overheating (for RMS-equipped loud­speakers, you can verify this in Compass RMS), a reduction
in SPL may be necessary. If, after a reduction in SPL and an
appropriate cooling period, the On/Status LED continues to
flash red (does not return to solid green), contact Meyer
Sound Technical Support.

If the On/Status LED flashes red and the loudspeaker does
not output audio, contact Meyer Sound Technical Support
immediately.

CAUTION: If a 750-LFC loudspeaker system

consistently overheats before reaching the
desired SPL, consider adding more units to the sys­tem.

NOTE: During startup, the On/Status LED

flashes multiple colors successively. For more
information on the power on sequence, see
“Intelligent AC Power Supply” on page 12.

TIP: When the 750-LFC is connected to an RMS

network, the Compass RMS software provides
additional feedback on the loudspeaker’s hardware
status and operating temperature. For more informa­tion, see Chapter 5, “Remote Monitoring System
(RMS) Option.”

17

CHAPTER 3: AMPLIFICATION AND AUDIO

18

CHAPTER 4: QUICKFLY RIGGING

IMPORTANT SAFETY CONSIDERATIONS!

When installing Meyer Sound loudspeakers and subwoofers, the following precautions should always be observed:

■ All Meyer Sound products must be used in accordance

with local, state, federal, and industry regulations. It is
the owner’s and user’s responsibility to evaluate the reli­ability of any rigging method for their application. Rigging
should only be carried out by experienced professionals.

■ Use mounting and rigging hardware that has been rated

to meet or exceed the weight being hung.

■ Make sure to attach mounting hardware to the building’s

structural components (roof truss), and not just to the
wall surface.

■ Make sure bolts and eyebolts are tightened securely.

®

Meyer Sound recommends using Loctite

on all

threaded fasteners.

■ Inspect mounting and rigging hardware regularly. Imme-

diately replace any worn or damaged components.

750-LFC RIGGING OPTIONS

Table 2 summarizes the available rigging options for the 750-LFC. For complete information on rigging hardware, including
dimensions, weight, configuration, and load ratings, refer to the MG-LINA/750 Assembly Guide (PN 05.270.101.01) available
at www.meyersound.com

Table 2: 750-LFC Rigging Options

Model Weight Features Required Quick-

MRK-750 rigging kit

PN 40.271.009.01

MG-MINA/LINA/750
multipurpose grid with
750-LFC grid link kit
installed
PN 40.207.101.02

GLK-750-LFC
grid link upgrade kit
PN 40.207.301.01

MVP motor Vee plate
PN 40.215.184.01

PBF-LINA
pull-back frame
PN 40.271.080.01

MCF-750 (rigging)

caster frame
PN 40.271.070.02

MCF-750 (no rigging)

caster frame
PN 40.271.070.03

MPK-POLE 35 mm

PN 40.086.014.02

MPK-POLE 35 mm/M20

PN 40.010.972.01

.

25 lb

(11.3 kg)

38 lb

(17.2 kg)

2lb

(0.9 kg)

20 lb

(9.1 kg)

4 lb

(1.8 kg)

34 lb

(15.4 kg)

28.7 lb

(13.0 kg)

3 lb

(1.36 kg)

3.8 lb
(1.72 kg)

Required

Release Pins

Upgrade kit to allow the 750-LFC to be flown and ground­stacked with the MG-LINA//750 grid; includes hardware to do
the upgrade, captive GuideALinks and quick-release pins.

Supports arrays of 750-LFCs or mixed arrays of 750-LFCs and
LINA without transition hardware; accommodates a variety of
pickup configurations with four corner and 11 center pickup
points can also be used for groundstacking.
Alway use MAPP-XT to verify load ratings.

Includes two grid links to upgrade existing MG-MINA/LINA grids
(PN 40.207.101.01). These 2 rear links effectively increase the
load rating for the grid when attaching 750-LFCs. Alway use
MAPP-XT to verify load ratings.

Fine tunes the horizontal aim of arrays; compatible with MTG­LEO-M, MTG-LYON, MTG-1100, and MG-LEOPARD/900 grids.

Attaches to bottom of LINA, MINA, and 750-LFC arrays (to the
bottom cabinet) and provides pull-back for extreme array
downtilt.

Safely transports up to three 750-LFC cabinets. This caster
frame is for cabinets with equipped with MRK-750 rigging.

Safely transports up to three 750-LFC cabinets. This caster
frame is for cabinets with out rigging.

Adjustable 35 mm pole, 32–55 in long (38 mm adapter
included)

Fixed 35 mm pole with M20 slug on one end, 47 in long — —

1/4 x 0.53-in, PN 134.039
qty 8 included

1/4 x 0.90-in, PN 134.036
qty 10 included

1/4 x 0.90-in, PN 134.036
qty 2 included

—

1/4 x 0.90-in, PN 134.036
qty 2 included

1/14 x 0.90
PN 134.036
qty 4 included

no pins —

——

Shackles

—

5/8-in or

3/4-in

—

3/4-inch or

7/8-in

1/2-in

—

19

CHAPTER 4: QUICKFLY RIGGING

MG-MINA/LINA/750
Multipurpose Grid

Fitted with GLK for
improved load rating
when hanging 750-LFCs

(2) 750-LFCs

Low-frequency
enhancement

(6) LINAs

Primary array
coverage

Rigging Example, Mixed Array with 750-LFCs and LINAs

20

750-LFC OPERATING INSTRUCTIONS

!

GROUNDSTACKING 750-LFC
LOUDSPEAKERS

750-LFCs can be groundstacked up to three units high, with
or without the MRK-750 rigging kit. Protective plastic skids
are included on the bottom of the 750-LFC cabinet that align
with the slots on the cabinet top. Units can be stacked nor­mally or reversed for cardioid configurations. When ground­stacking 750-LFCs, make sure the skids for each unit align
with the slots in the cabinet tops. When equipped with the
MRK-750 rigging kit, the 750-LFC can be groundstacked on
the MG-LINA/750 grid with LINAs for mixed groundstacks.

750-LFC CARDIOID ARRAYS

The 750-LFC can be configured in cardioid arrays to reduce
undesirable low frequency leakage behind the loudspeakers.
The loudspeaker’s linearity ensures that cardioid patterns
behave accurately even at very high levels. Cardioid arrays are
achieved by placing three units coplanar to each other (in
either a groundstacked or flown array) with one unit facing the
opposite direction. Polarity and delay processing is applied to
the rear-facing unit, which yields output that cancels output
from the other loudspeakers normally present behind the
units.

NOTE: To achieve an accurate cardioid pattern,

you must use Meyer Sound’s MAPP prediction
software and the Galileo® GALAXY array processors.
Use MAPP to calculate the appropriate ratio of for­ward- to rear-facing loudspeakers, as well as the pro­cessor settings for polarity and delay. A myriad of
possible cardioid and directional configurations can be
calculated and predicted with MAPP. For more infor­mation, contact Meyer Sound Technical Support.

NOTE: 750-LFCs need not be equipped with the

MRK-750 rigging kit for groundstacked cardioid con­figurations of up to three cabinets.

Figure 15: 750-LFC groundstacks: with rigging (left); cardioid without
rigging (right)

CAUTION: As a safety precaution, to avoid tip-

ping, a maximum of three cabinets is sup-

ported for groundstacked 750-LFCs.

NOTE: 750-LFCs need not be equipped with

the MRK-750 rigging kit for secure ground-

stacking of up to three cabinets.

NOTE: 750-LFC cardioid arrays can also be

flown from the MG-MINA/LINA/750 grid. For
more information, see the MG-MINA/LINA/750
Assembly Guide (PN 05.270.101.01) at www.meyer-

sound.com.

MRK-750 RIGGING KIT

The optional MRK-750 rigging kit allows the 750-LFC to be
flown and groundstacked with the MG-MINA/LINA/750 mul­tipurpose grid. The kit also allows 750-LFCs to be flown and
groundstacked with LINA with no transition hardware. The rig­ging kit is available as a factory-installed option or as a field
upgrade and uses rugged GuideALinks and intuitive quick­release pins to securely link adjacent loudspeakers in flown
and groundstacked array configurations.

NOTE: For more information on the MRK-750

rigging kit, including its kit contents, weight,
and installation instructions, refer to the MG­MINA/LINA/750 Assembly Guide (PN 05.270.101.01)
available at www.meyersound.com

.

21

CHAPTER 4: QUICKFLY RIGGING

!

750-LFC GUIDEALINKS

When equipped with the MRK-750 rigging kit, the 750-LFC
includes six captive GuideALinks and six mating link slots
that link to adjacent units in flown and groundstacked arrays.
Located at the bottom of the cabinet, GuideALinks drop
down and into the link slots of the cabinet below it. GuideA­Links extend and retract with knobs and are secured with two
quick-release pins: one each in the top and bottom cabinets.
GuideALinks accommodate reversed units for cardioid
arrays. The MRK-750 rigging kit includes eight 1/4 x 0.53-in
quick-release pins.

GLK-750 Grid Link Kit

The original MG-MINA grid (PN 40.207.101.01) includes only
the front and the middle links that allow flying MINAs or
LINAS from it. We recommend NOT using the middle link to
hang the 750-LFC because its load rating is about half of its
maximum capability.

We recommend using the updated version MG­MINA/LINA/750 (PN 40.207.101.02) to hang 750-LFCs. You
can also update existing grids with the GLK-750-LFC grid
link upgrade kit (PN 40.207.301.01), which includes the two
rear links and installation hardware. Using the rear links,
instead of the middle, effectively increases the load rating
for the grid when attaching 750-LFCs.

CAUTION: Always use MAPP-XT to verify load

ratings. Under no circumstance should all six
links be used at the same time as this will not add any
load capability. In fact the load capacity will decrease
by about half of that provided by the rear links
because it cannot be determined which links are
actually under tension.

Figure 16: 750-LFCs with MRK-750 Rigging Kit, GuideALinks

The 750-LFC’s GuideALinks accommodate both 750-LFCs
and LINAs without transition hardware. The front and rear
GuideALinks are used when flying the 750-LFC below the
MG-LINA/750 grid, or when flying it below another 750-LFC
(see Figure 18). The configuration of the 750-LFC’s GuideA­Links, front and rear, determines its splay angle.

22

Figure 17: 750-LFC rigging grid

750-LFC OPERATING INSTRUCTIONS

!

Figure 18: Flown 750-LFC with GuideALink Attachments

The 750-LFC’s four corner link slots on the top of the cabi­net accept GuideALinks from flown 750-LFCs. The front and
rear/middle link connect to LINA GuideALinks slots when
flying LINAs below the 750-LFC (see Figure 18). The config­uration of 750-LFCs GuideALinks, front and rear/middle,
determines the LINAs splay angle.

The MG-MINA/LINA/750 grid's front and rear/middle link
slots also accept links from the 750-LFC grid when ground­stacking the 750-LFC (see Figure 19). The configuration of
the grid’s links, whether set to A or B, determines the angle
of attachment for the groundstacked 750-LFC.

Figure 19: Groundstacked 750-LFC with GuideALink Attachments

The 750-LFC’s front and rear GuideALinks are used when
attaching a LINA groundstack on top of the 750-LFC (see
Figure 19).

CAUTION: Do not use the rear/middle GuideA-

Links when flying the 750-LFC below the MG­MINA/LINA/750 grid or when flying below another
750-LFC. Always use the front and rear GuideALinks
when flying the 750-LFC.

NOTE: When flying the 750-LFC below the

MG-MINA/LINA/750 grid, a splay angle of
0 degrees is recommended for the top cabinet (rear
GuideALinks set to 0, front GuideALinks set to 0) to
ensure that the cabinet aligns with any lasers or incli­nometers mounted on the grid. To add tilt to the top
cabinet, the actual grid should instead be tilted. For
more information, see available at www.meyer-

sound.com).

23

CHAPTER 4: QUICKFLY RIGGING

750-LFC Splay Angles

The front and rear GuideALinks attach at angles of 0, 1.5,

3.25 or 4.75 degrees, thereby allowing curved arrays for the
750-LFC. Because the cabinet’s front and rear GuideALinks
are symmetrical, the curved arrays can also include cardioid
configurations.

There are a several third-party poles and adapters to mount
Meyer Sound loudspeakers on top of the 750-LFC.

Meyer Sound offers these accessories for this purpose:

■ Pole stand-adapter kit 35 mm (PN 40.010.971.01)

■ Adjustable 35 mm pole: 32 –55 in long (PN 40.086.014.02)

■ Fixed 35 mm pole with M20 slug on one end: 47 in long

(PN 40.010.972.01)

Figure 20: 750-LFC Front GuideALinks Label

The labels next to the front and rear GuideALinks indicate the
splay angle between cabinets (when the opposing links are
set to 0 degrees). As the links are moved down, the splay
angles increase. To stow the GuideALinks, move them all the
way up to stow and pin them.

NOTE: Curved 750-LFC arrays do not provide

directionality for low-frequency content. The
curved array capability of the 750-LFC is provided only
for aesthetic reasons, to complement, if desired, the
curvature of LINA arrays.

POLE-MOUNT RECEPTACLE

You can mount Meyer Sound loudspeakers on top of the
750-LFC with a heavy-duty pole and pole-stand adapter.

The 750-LFC includes a pole-mount receptacle:

■ U.S. version: 1 1/2 in (38 mm)

■ E.U. version: 1 3/8 in (35 mm, M20 thread at the bottom)

Figure 21: Pole and Pole-Mount Adapter: 750-LFC with LINA (left) and
ULTRA series speaker (right)

The following Meyer Sound loudspeakers can be mounted
on top of the 750-LFC. Make sure that the pole and pole­mount adapter can support the weight of the mounted loud­speakers and that they are installed according to the manu­facturer’s instructions.

■ One MINA or LINA with MUB-MINA U-bracket

(47 lb, 21.3 kg)

■ Two MINA or LINA with MUB-MINA U-bracket

(90 lb, 40.8 kg).

NOTE: This configuration is at the weight limit for

most poles, so use extreme caution as it could
become unstable. We recommend using two 750­LFCs and two LINAs on top with a short pole for this
configuration.

24

■ One UPA-1P or UPA-2P (77 lb, 34.9 kg)

!

!

!

■ One UPJ-1P (46 lb, 20.9 kg)

■ One UPJunior (28 lb, 12.7 kg)

■ Two UPJuniors with MUB-UPJunior U-bracket and

MAAM-UPJunior array adapter (70 lb, 31.8 kg)

CAUTION: Make sure the pole and pole-mount

adapter can support the total weight of the
mounted loudspeakers. In particular, heavier loud­speakers are less stable on taller pole mounts.
Observe all safety precautions specified by the pole
manufacturer.

MCF 750 CASTER FRAME

The MCF-750 is highly durable and easy to attach to 750­LFC subwoofers, making it easy to assemble or disassem­ble by using blocks of up to three 750-LFC subwoofers.

The heavy-duty MCF-750 caster frame has two options
(shown below):

750-LFC OPERATING INSTRUCTIONS

■ PN 40.271.070.02: Transport 750-LFCs fitted with rig-

ging frames

■ PN 40.271.070.03: Transport 750-LFCs without rigging

frames

Figure 22: MCF 750 Caster Frames: with rigging (top), no rigging
(bottom)

Figure 23: MCF 750 Caster Frame

TIP: You can also transport the MG-

MINA/LINA/750 top grid attached to the top

750-LFC on a stack.

In addition to transport, the MCF-750 frame supports 750­LFC subwoofers in a ground-stacked configuration.

CAUTION: When ground-stacking 750-LFC

subwoofers using the MCF-750 caster frame,
make sure all four caster wheels are blocked so it
does not roll.

CAUTION: Do not exceed three 750-LFCs

stacked on a block to avoid tipping them over.

When deploying and striking a 750-LFC array, the MCF-750
caster frame can support its weight.

25

CHAPTER 4: QUICKFLY RIGGING

Figure 24: Three 750-LFCs without rigging on a dolly secured by a strap

NOTE: For safety reasons and to avoid any

damage to the enclosures, use straps when
transporting a stack if the cabinets are not fitted with
the MRK-750 rigging kit. The MCF-750 includes slots
on the sides for this purpose.

26

CHAPTER 5: REMOTE MONITORING SYSTEM (RMS) OPTION

The RMS module is optional and should be ordered from the
factory. RMS allows connecting the loudspeaker to an RMS
network to receive real-time status reports about power
usage for multiple Meyer Sound loudspeakers from a Mac or
Windows-based computer. The RMS host computer com­municates with Meyer Sound loudspeakers (equipped with
RMS modules) via RMServer

™

, a compact, Ethernet-based
hardware unit with two FT-10 ports. RMServer stores system
configurations internally, eliminating most manual data entry.
Systems can be monitored from a computer at front-of­house, backstage, or from anywhere within the venue over
WiFi.

NOTE: For the latest RMS system require-

ments, visit the Meyer Sound website

(http://www.meyersound.com

).

NOTE: RMS does not control AC power.

COMPASS RMS SOFTWARE

Compass RMS™ software provides extensive system status
and performance data for each loudspeaker, including
amplifier voltage, limiting activity, power output, fan and
driver status, as well as mute and solo capability. Loud­speakers are added to the RMS network and assigned a
node name during a one-time discovery procedure. Once
loudspeakers are identified on the RMS network, they
appear in Compass RMS as icons that can be customized
to suit your needs.

Individual loudspeakers can be physically identified with the
Wink option in RMS, which lights the Wink LED on the RMS
module for that particular loudspeaker. Conversely, a loud­speaker can be identified in Compass RMS by pressing the
Identify button on the loudspeaker’s RMS module.

Loudspeaker icons can be arranged in Compass RMS and
saved as pages to represent how the loudspeakers have
been deployed in the system. Multiple pages can be saved
and recalled for specific performances and venues.

RMS MODULE

The 750-LFC RMS user panel includes an Identify button,
Remote Mute switch, Wink/Activity LED, and two Network
connectors.

750-LFC RMS Module

NOTE: The Identify button and Wink/Activity

LED on the RMS user panel are used exclu­sively by RMS and have no effect on the acoustical or
electrical activity of the loudspeaker.

Compass RMS Window

Identify Button

The Identify button serves the following functions:

■ If the loudspeaker has not yet been discovered on the

RMS network (Wink/Activity LED not lit), press the Iden­tify button to discover it.

■ To remove the loudspeaker from the RMS network, press

and hold the Identify button during startup (see “Reset­ting the RMS Module” on page 28).

■ To wink a discovered loudspeaker, press the Identify but-

ton. The Wink LED on the loudspeaker icon in Compass
RMS lights up and the Wink/Activity LED on the loud­speaker’s RMS user panel turns solid green. Press the
Identify button again to unwink the loudspeaker.

27

CHAPTER 5: REMOTE MONITORING SYSTEM (RMS) OPTION

TIP: The Wink function is useful for identifying

the physical loudspeaker corresponding to a

loudspeaker icon in Compass RMS.

TIP: The loudspeaker can also be winked by

clicking the Wink button on the loudspeaker

icon in Compass RMS.

Wink/Activity LED (Green)

The green Wink/Activity LED indicates the status of the
loudspeaker:

■ During startup, the LED flashes green 10 times.

■ If the loudspeaker has not yet been discovered on the

RMS network, the LED is not lit after startup.

■ If the loudspeaker has been successfully discovered on

the RMS network, the LED flashes green continuously
and flashes more rapidly with increased data activity.

■ When the loudspeaker is winked (click the Wink button in

Compass or press the Identify button on the RMS user
panel), the LED lights solid green until the loudspeaker is
unwinked.

Remote Mute Switch

The recessed Remote Mute switch on the 750-LFC RMS
module determines whether Compass RMS can control
muting and soloing of the loudspeaker. The 750-LFC ships
from the factory with the switch enabled.

RMS Network Connectors

The Weidmuller 2-conductor, locking connectors transfer
data to and from the RMS network. Two connectors are pro­vided to allow for easy connection of multiple (daisy­chained) loudspeakers on the network. Included with each
RMS-equipped loudspeaker are RMS cable connectors and
mounting blocks for constructing RMS cables. The RMS
blocks allow cables to be securely attached to the RMS
module with screws.

NEURON ID FOR RMS MODULE

Each RMS module has a unique 12-character Neuron ID
(NID) that identifies the loudspeaker on the network. The
NID is automatically detected by RMServer but can also be
entered manually, if necessary, when configuring RMS sys­tems in Compass RMS without loudspeakers present. The
NID label is located on the RMS user panel near the orange
Network connectors.

RESETTING THE RMS MODULE

You can use the Identify button to reset the 750-LFC RMS
module when powering on the loudspeaker. This will cause
the module to be removed from the RMS network.

To reset the RMS module:

1. Power down the loudspeaker.

2. Press and hold the Identify button.

3. While continuing to hold down the Identify button, power
on the loudspeaker.

Remote Mute Switch

■ Disable: When the Remote Mute switch is set to Disable

(to the left), the loudspeaker cannot be muted or soloed
from Compass RMS.

■ Enable: When the Remote Mute switch is set to Enable

(to the right), the loudspeaker can be muted and soloed
from Compass RMS.

NOTE: Compass RMS also allows you to dis-

able Mute and Solo functions to eliminate any

possibility of accidentally muting loudspeakers.

28

4. After the Wink/Status LED flashes on and off, release the
Identify button. The RMS module is reset and the loud­speaker is removed from the RMS network.

CHAPTER 6: SYSTEM DESIGN AND INTEGRATION TOOLS

This chapter introduces MAPP, Meyer Sound’s patented sys­tem design tool, and SIM 3, a comprehensive system for
measurement and analysis.

MAPP SYSTEM DESIGN TOOL

MAPP is a powerful, cross-platform application for accu­rately predicting the coverage pattern, frequency response,
phase response, impulse response, and SPL capability of
single or arrayed Meyer Sound loudspeakers.

MAPP System Design Tool

Whether planning for fixed installations or for tours with mul­tiple venues, you can use MAPP to accurately predict the
appropriate loudspeaker deployment for each job, complete
with coverage data, system delay and equalization settings,
rigging information, and detailed design illustrations. MAPP’s
accurate, high-resolution predictions ensure that systems will
perform as expected, thereby eliminating unexpected cover­age problems and minimizing onsite adjustments.

The key to the accuracy of MAPP’s predictions is Meyer
Sound’s exhaustive database of loudspeaker measurements.
Performance predictions for each loudspeaker are based on
720 1/48th-octave-band measurements taken with a SIM
audio analyzer in the Meyer Sound anechoic chamber. The
extraordinary consistency between Meyer Sound loudspeak­ers guarantees that predictions from MAPP will closely match
their actual performance.

MAPP client software lets you configure Meyer Sound loud­speaker systems and define the environment in which they
operate, including air temperature, pressure, humidity, and
even the location and composition of surfaces. You can also
import CAD (.DXF) files containing detailed venue information
to act as a visual aid.

MAPP prediction requests are sent by the client software to
Meyer Sound servers, where complex, high-resolution (mag­nitude and phase) polar data is processed with sophisticated
acoustical prediction algorithms. The resulting predictions
are then displayed in the MAPP client software.

TIP: Meyer Sound offers seminars and webinars

on using MAPP. For more information, visit

www.meyersound.com

.

MAPP Capabilities

With MAPP, you can:

■ Simulate different loudspeaker configurations to refine

system design and determine the best coverage for
intended audience areas

■ Monitor loudspeaker interactions to locate constructive

and destructive interferences so that loudspeakers can
be re-aimed and repositioned as necessary

■ Place microphones anywhere in the sound field and pre-

dict loudspeaker frequency response, phase response,
and sound pressure levels as measured at each micro­phone position

■ Determine delay settings for fill loudspeakers using the

Inverse Fast Fourier Transform feature

■ Preview the results of Galileo or Galileo Callisto process-

ing to determine optimum settings for the best system
response

■ Automatically calculate load information for arrays to

determine rigging capacity, front-to-back weight distribu­tion, and center of gravity location

■ Generate and export system images and full-system PDF

reports for client presentations

29

CHAPTER 6: SYSTEM DESIGN AND INTEGRATION TOOLS

SIM 3 MEASUREMENT SYSTEM

The SIM 3 audio analyzer is a high-resolution audio measure­ment system comprised of software, hardware, microphones,
and accessory cables. SIM 3 is optimized for measuring
audio frequencies with resolutions down to 1/48th of an
octave, allowing you to apply precise corrections to balance
system response using frequency and phase domain infor­mation.

Source Independent Measurement Technique

The SIM 3 audio analyzer implements Meyer Sound’s source
independent measurement technique, a dual-channel
method that accommodates statistically unpredictable exci­tation signals. Any excitation signal within a desired frequency
range can be used to obtain highly accurate measurements
for acoustical or electronic systems.

For example, during a performance, both the input signal and
the measured output of the loudspeaker system can be cap­tured and used as a SIM 3 test signal, so you can:

■ View measurement data as amplitude versus time

(impulse response) or amplitude and phase versus fre­quency (frequency response)

SIM 3 Applications

SIM 3’s main applications are testing and aligning loud­speaker systems, which entails:

■ Measuring propagation delays between subsystems to

determine appropriate polarities and delay times

■ Measuring variations in frequency response caused by the

acoustical environment and the placement and interaction
of loudspeakers to determine corrective equalization

■ Optimizing subwoofer integrations

■ Optimizing loudspeaker arrays

SIM 3 can also be used in the following applications:

■ Microphone calibration and equalization

■ Transducer evaluation and correction

■ Echo detection and analysis

■ Vibration analysis

■ Architectural acoustics

■ Utilize a single-channel spectrum mode

■ View frequency domain data with a logarithmic frequency

axis

■ Determine and internally compensate for propagation

delays using the SIM 3 Delay Finder

30

APPENDIX A: RAIN HOODS

!

Weather-protected 750-LFCs include a rain hood for indoor/outdoor touring and sheltered outdoor installations. Meyer
Sound offers two rainhood models: A fixed rigid rainhood for permanent installations and a foldable hood for portable appli­cations. Please specify your rainhood when placing the order.

Figure 25: 750-LFC with rigid rain hood (left) and foldable rain hood (right)

750-LFC RIGID RAIN HOOD

The 750-LFC rigid removable rain hood is easily attached and removed with the included four screws.

To attach the 750-LFC rigid rain hood:

1. Attach any required cables to the 750-LFC loudspeaker.

2. Attach the rain hood to the user panel, and secure it to the center of the panel with its four 6/32 screws.

3. Make sure to tighten the screws to create a good seal against the user panel.

750-LFC FOLDABLE RAIN HOOD

The 750-LFC foldable rain hood is installed on the unit when shipped. Four screws secure its frame permanently.

To use the 750-LFC foldable rain hood:

1. Detach the velcro straps and extend the rainhood

2. Extend the lower flap for splash protection.

3. Attach any required cables to the 750-LFC.

The clear windows let you easily locate the connectors on the user panel.

4. To stow the rainhood, reverse the steps.

CAUTION: The weather-protected 750-LFC must be mounted with a 0-degree tilt, or preferably with a slight

downtilt. This shields the driver from the elements and does not accumulate water.

31

APPENDIX A: RAIN HOODS

32

APPENDIX B: 750-LFC DIMENSIONS

554mm

21.8in

478mm

18.8in

515mm

20.3in

530mm

20.9in

6mm

.2in

279mm

11.0in

248mm

9.8in

1 1/2

[38mm] U.S.

1 3/8

[35mm] E.U.

M20 thread at the bottom

750-LFC NO RIGGING

WEIGHT: 89 LBS

530mm

20.9in

6mm

.2in

70.9mm

2.79in

601.2mm

23.67in

279mm

11.0in

248mm

9.8in

750-LFC dimensions without rigging

750-LFC W/P dimensions without rigging and rainhood installed

33

APPENDIX B: 750-LFC DIMENSIONS

471mm

18.55in

547mm

21.55in

519mm

20.43in

750-LFC W/RIGGING

WEIGHT: 105 LBS

1 1/2

[38mm] U.S.

1 3/8

[35mm] E.U.

M20 thread at the bottom

530mm

20.88in

6mm

.25in

251mm

9.88in

277mm

10.90in

530mm

20.88in

6mm
.25in

71.1mm

2.80in

601.5mm

23.68in

251mm

9.88in

277mm

10.90in

750-LFC W/P dimensions with rigging

750-LFC W/P dimensions with rigging and rainhood installed

NOTE: For dimensions and weight for the MG-LINA top grid and MCF-750 caster frame, refer to the MG-LINA/

750 Assembly Guide (PN 05.270.101.01) available at www.meyersound.com

.

34

APPENDIX C: 750-LFC SPECIFICATIONS

Loudspeaker system predictions for coverage and SPL are available in Meyer Sound’s MAPP prediction software, which
can be found on the Meyer Sound website: http://www.meyersound.com

ACOUSTICAL

Operating Frequency Range

Frequency Response

Phase Response 43 Hz – 110 Hz ±30 degrees

Linear Peak SPL

TRANSDUCERS

Low Frequency One 15-in dual-coil, long-excursion cone driver

Coverage 360° (single unit); varies with number of units and configuration

AUDIO INPUT

Type Differential, electronically balanced

Maximum Common Mode Range ±15 V DC, clamped to earth for voltage transient protection

Connectors XLR 3-pin or 5-pin female input

Input Impedance 10 kΩ differential between pins 2 and 3

Wiring Pin 1: Chassis/earth through 1 kΩ, 1000 pF, 15 V clamped network to provide virtual

DC Blocking Differential DC blocking up to the maximum common mode voltage

CMRR >50 dB, typically 80 dB (50 Hz – 500 Hz)

RF Filter Common mode: 425 kHz

TIM Filter Integral to signal processing (<80 kHz)

Nominal Input Sensitivity 6.0 dBV (2.0 V rms) continuous is typically the onset of limiting for noise and music

Input Level Audio source must be capable of producing +20 dBV (10 V rms) into 600 ohms to pro-

35 Hz – 125 Hz
Note: Recommended maximum operating frequency range.
Response depends on loading conditions and room acoustics.

37 – 110 Hz (±4 dB)

Note: Measured in half-space with pink noise at 4 m, 1/3-octave frequency resolution.

124.5 dB (M-noise), 124.5 dB (Pink-Noise), 126 dB (B-Noise)
Note: Linear Peak SPL is measured in half-space at 4 m referred to 1 m.

Loudspeaker SPL compression measured at the onset of limiting, 2-hour duration, and
50° C ambient temperature is <2 dB.

M-noise is a full bandwidth, (10Hz–22.5kHz) test signal developed by Meyer Sound to
better measure the loudspeaker’s music performance. It has a constant instantaneous
peak level in octave bands, a crest factor that increases with frequency, and a full band­width Peak to RMS ratio of 18 dB.

Pink noise is a full bandwidth test signal with a peak-to-RMS ratio of 12.5 dB.
B-noise is a Meyer Sound test signal that ensures measurements reflect system behavior

when reproducing the most common input spectrum, and verify there is still headroom
over pink noise.

XLR 3-pin or 5-pin male loop output
Note: XLR 5-pin connectors accommodate both balanced audio and RMS signals.

ground lift at audio frequencies
Pin 2: Signal (+)
Pin 3: Signal (–)
Pin 4: RMS (polarity insensitive)
Pin 5: RMS (polarity insensitive)
Case: Earth ground and chassis
Note: Pins 4 and 5 (RMS) included only with XLR 5-pin connectors.

Differential mode: 142 kHz

duce the maximum peak SPL over the operating bandwidth of the loudspeaker

.

35

APPENDIX C: 750-LFC SPECIFICATIONS

AMPLIFIER

Type 2-channel, open-loop, class D

Cooling Convection

AC POWER

Connectors powerCON 20 input with loop output

Safety Rated Voltage Range 100–240 V AC, 50–60 Hz

Turn-on/off Points Turn-on: 90 V AC; Turn-off: none; internal fuse protection above 265 V AC

Current Draw 115 V AC 230 V AC 100 V AC

Idle 0.39 A rms 0.38 A rms 0.42 A rms

Maximum Long-Term Continuous 5.3 A rms 2.7 A rms 6.2 A rms

Burst 9.2 A rms 4.4 A rms 10.7 A rms

Maximum Instantaneous Peak 15.3 A peak 7.8 A peak 18 A peak

PHYSICAL

Enclosure Multi-ply hardwood

Finish Black textured

Protective Grille Hex-stamped steel with acoustical black mesh

Rigging Optional MRK-750 rigging kit with endframes and captive GuideALinks (0, 1.5, 3.25, and

4.75 degree splay angles), quick-release pins, and detachable side handles

Pole Mount U.S. version: 1 1/2-in (38 mm)

E.U. version: 1 3/8-in (35 mm and M20 thread at the bottom)

Dimensions 21.80 in (554 mm) W 20.30 in (515 mm) H 20.88 in (530 mm) D

Dimensions (with rigging) 21.55 in (547 mm) W 20.43 in (519 mm) H 20.88 in (530 mm) D

Weight 89 lb (40.3 kg)

Weight (with rigging) 105 lb (47.6 kg)

ENVIRONMENTAL

Operating Temperature 0° C to +45° C

Non Operating Temperature –40° C to +75° C

Humidity To 95% at 45° C (non-condensing)

Operating Altitude To 5,000 m (16,404 ft)

Non Operating Altitude To 12,000 m (39,000 ft)

Shock 30 g 11 msec half-sine on each of 6 sides

Vibration 10 Hz – 55 Hz (0.010 m peak-to-peak excursion)

36

750-LFC OPERATING INSTRUCTIONS

Federal Communications Commission (FCC) Statement

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the
FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is
operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required
to correct the interference at their own expense.

This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may
not cause harmful interference, and (2) this device must accept any interference received, including interference that may
cause undesired operation.

Industry Canada Compliance Statement

This Class A digital apparatus complies with Canadian ICES-003.

Avis De Conformité à La Réglementation D'industrie Canada

Cet appareil numérique de la classe A est conforme à la norme NMB-003 du Canada.

EN 55032 (CISPR 32) Statement

Warning: This equipment is compliant with Class A of CISPR 32. In a residential environment this equipment may cause
radio interference

37

APPENDIX C: 750-LFC SPECIFICATIONS

38

Meyer Sound Laboratories Inc.
2832 San Pablo Avenue
Berkeley, CA 94702
+1 510 486.1166
www.meyersound.com

© 2018

Meyer Sound. All rights reserved.

750-LFC Operating Instructions

PN 05.271.005.01 B